This invention relates generally to a burner assembly and, more particularly, to a burner assembly for use in a recuperative radiant tube heating system of the single-ended type. A single-ended recuperative (SER) radiant tube heating system is disclosed in Collier U.S. Pat. No. 4,705,022.
In general, such a system comprises an outer heat-resistant radiant tube having a closed forward end. Located within the outer radiant tube is an elongated recuperator tube which coacts with the radiant tube to define an annular exhaust passage for the flow of hot exhaust gases produced by a burner assembly. The latter includes a burner head which is supplied with gaseous fuel by way of a gas supply pipe.
In operation, gaseous fuel and combustion air are supplied to the burner head and are mixed therein to produce an intense flame which shoots along the forward end portion of the recuperator tube to heat the latter and the radiant tube. Exhaust gases discharged from the forward end of the recuperator tube strike the closed end of the radiant tube and flow reversely in the annular passage between the two tubes in order to further heat the radiant tube and also to preheat the combustion air flowing toward the burner head.
The burner assembly disclosed in the Collier patent is primarily designed for use with natural gas (e.g., methane) which has a low heat value when compared to a gas such as butane. When butane is used as fuel in the burner of the Collier patent, its high heat value causes the gas to burn before the gas can mix thoroughly with the combustion air. This results in unclean burning of the fuel.